fix: review findings on week start and settings motion

- The last week start is saved with the activity, so a rotation no
  longer draws one frame in the locale's order before the stored day.
- A backup with "week_start": null restores Automatic instead of
  rejecting the whole file.
- Under reduced motion a settings sub-page fades in, matching its exit.
- LocalWeekStart, rememberWeekStart and one shared rememberLocale move
  to ui/common; the picker, the day buttons and the summaries use them.
- The "Week starts on" row shows the day Automatic resolves to.

app/src/main/java/de/jeanlucmakiola/clockula/MainActivity.kt

@@ -13,6 +13,7 @@ import androidx.compose.runtime.CompositionLocalProvider
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
@@ -21,7 +22,7 @@ import de.jeanlucmakiola.clockula.bedtime.BedtimeIntents
 import de.jeanlucmakiola.clockula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.clockula.domain.WeekStartPref
 import de.jeanlucmakiola.clockula.interop.InteropIntents
-import de.jeanlucmakiola.clockula.ui.alarms.LocalWeekStart
+import de.jeanlucmakiola.clockula.ui.common.LocalWeekStart
 import de.jeanlucmakiola.clockula.ui.crash.CrashReportActivity
 import de.jeanlucmakiola.clockula.ui.shell.ClockulaShell
 import de.jeanlucmakiola.clockula.ui.shell.ShellNavigation
@@ -100,9 +101,13 @@ class MainActivity : ComponentActivity() {
                 .collectAsStateWithLifecycle(initialValue = Appearance())
             val darkTheme = appearance.themeMode.isDark(isSystemInDarkTheme())
             // Read here once rather than by each screen that lays out a week:
-            // the alarm list, the alarm editor and bedtime all do (#30).
+            // the alarm list, the alarm editor and bedtime all do (#30). The
+            // last value is saved with the activity, so a rotation or a theme
+            // change doesn't draw one frame in the locale's order first.
+            var lastWeekStart by rememberSaveable { mutableStateOf(WeekStartPref.AUTO) }
             val weekStart by settingsPrefs.weekStart
-                .collectAsStateWithLifecycle(initialValue = WeekStartPref.Auto)
+                .collectAsStateWithLifecycle(initialValue = WeekStartPref.parse(lastWeekStart))
+            LaunchedEffect(weekStart) { lastWeekStart = weekStart.storageValue }
 
             // The system bars follow the *resolved* theme, not the device night
             // flag: with the device dark and ThemeMode.LIGHT stored, deriving the

app/src/main/java/de/jeanlucmakiola/clockula/data/backup/BackupDto.kt

@@ -1,6 +1,5 @@
 package de.jeanlucmakiola.clockula.data.backup
 
-import de.jeanlucmakiola.clockula.domain.WeekStartPref
 import de.jeanlucmakiola.clockula.domain.bedtime.BedtimeSettings
 import de.jeanlucmakiola.clockula.domain.ring.SilenceAfter
 import kotlinx.serialization.SerialName
@@ -113,8 +112,8 @@ data class SettingsDto(
     @SerialName("screen_saver_night_mode") val screenSaverNightMode: Boolean = false,
     /** Absent (a file from before #26) or out of range keeps the tile's default. */
     @SerialName("quick_tile_duration_millis") val quickTileDurationMillis: Long? = null,
-    /** Absent (a file from before #30) or unrecognised follows the locale, the default. */
-    @SerialName("week_start") val weekStart: String = WeekStartPref.AUTO,
+    /** Absent (a file from before #30), null or unrecognised follows the locale, the default. */
+    @SerialName("week_start") val weekStart: String? = null,
 )
 
 /**

app/src/main/java/de/jeanlucmakiola/clockula/ui/alarms/AlarmRow.kt

@@ -16,12 +16,8 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.ProvidableCompositionLocal
-import androidx.compose.runtime.compositionLocalOf
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.CustomAccessibilityAction
@@ -40,17 +36,15 @@ import de.jeanlucmakiola.clockula.domain.PauseRange
 import de.jeanlucmakiola.clockula.domain.RepeatDays
 import de.jeanlucmakiola.clockula.domain.RepeatDaysSummary
 import de.jeanlucmakiola.clockula.domain.RepeatSummary
-import de.jeanlucmakiola.clockula.domain.WeekStartPref
 import de.jeanlucmakiola.clockula.domain.format.NextFireLabel
-import de.jeanlucmakiola.clockula.domain.resolveFirstDay
 import de.jeanlucmakiola.clockula.ui.common.SwipeToDelete
 import de.jeanlucmakiola.clockula.ui.common.rememberAlarmTimeFormatter
+import de.jeanlucmakiola.clockula.ui.common.rememberLocale
+import de.jeanlucmakiola.clockula.ui.common.rememberWeekStart
 import de.jeanlucmakiola.floret.components.GroupedListInset
 import de.jeanlucmakiola.floret.components.GroupedSurface
 import de.jeanlucmakiola.floret.components.Position
-import java.time.DayOfWeek
 import java.time.format.TextStyle
-import java.util.Locale
 
 /**
  * A standalone alarm card. The time and switch share the first line, leaving
@@ -270,26 +264,3 @@ internal fun repeatSummaryText(repeatDays: RepeatDays): String {
         }
     }
 }
-
-/**
- * The stored "Week starts on" choice (#30), provided once by `MainActivity` for
- * every screen that lays out a week. Auto outside it, as in a preview.
- */
-internal val LocalWeekStart: ProvidableCompositionLocal<WeekStartPref> =
-    compositionLocalOf { WeekStartPref.Auto }
-
-/** The chosen first day of week, or the locale's own, re-read with the configuration. */
-@Composable
-internal fun rememberWeekStart(): DayOfWeek {
-    val locale = rememberLocale()
-    val weekStart = LocalWeekStart.current
-    return remember(locale, weekStart) { weekStart.resolveFirstDay(locale) }
-}
-
-@Composable
-private fun rememberLocale(): Locale {
-    // Keyed on the configuration, so a language change re-reads both the
-    // locale's day names and where its week begins.
-    val configuration = LocalConfiguration.current
-    return remember(configuration) { Locale.getDefault() }
-}

app/src/main/java/de/jeanlucmakiola/clockula/ui/alarms/RepeatDaySelector.kt

@@ -8,20 +8,19 @@ import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
 import androidx.compose.material3.Text
 import androidx.compose.material3.ToggleButton
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.semantics.contentDescription
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.clockula.domain.RepeatDays
 import de.jeanlucmakiola.clockula.domain.RepeatDaysOrder
+import de.jeanlucmakiola.clockula.ui.common.rememberLocale
+import de.jeanlucmakiola.clockula.ui.common.rememberWeekStart
 import de.jeanlucmakiola.floret.components.GroupedListInset
 import de.jeanlucmakiola.floret.components.GroupedSurface
 import de.jeanlucmakiola.floret.components.Position
 import java.time.DayOfWeek
 import java.time.format.TextStyle
-import java.util.Locale
 
 /**
  * Seven equal toggle buttons in one row — the Expressive round↔squircle morph
@@ -39,8 +38,7 @@ internal fun RepeatDaySelector(
     modifier: Modifier = Modifier,
     position: Position = Position.Alone,
 ) {
-    val configuration = LocalConfiguration.current
-    val locale = remember(configuration) { Locale.getDefault() }
+    val locale = rememberLocale()
     val days = RepeatDaysOrder.startingAt(rememberWeekStart())
 
     GroupedSurface(

app/src/main/java/de/jeanlucmakiola/clockula/ui/common/WeekStart.kt

@@ -0,0 +1,37 @@
+package de.jeanlucmakiola.clockula.ui.common
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.ProvidableCompositionLocal
+import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalConfiguration
+import de.jeanlucmakiola.clockula.domain.WeekStartPref
+import de.jeanlucmakiola.clockula.domain.resolveFirstDay
+import java.time.DayOfWeek
+import java.util.Locale
+
+/**
+ * The stored "Week starts on" choice (#30), provided once by `MainActivity` for
+ * every screen that lays out a week. Auto outside it, as in a preview.
+ */
+internal val LocalWeekStart: ProvidableCompositionLocal<WeekStartPref> =
+    compositionLocalOf { WeekStartPref.Auto }
+
+/** The chosen first day of week, or the locale's own, re-read with the configuration. */
+@Composable
+internal fun rememberWeekStart(): DayOfWeek {
+    val locale = rememberLocale()
+    val weekStart = LocalWeekStart.current
+    return remember(locale, weekStart) { weekStart.resolveFirstDay(locale) }
+}
+
+/**
+ * The locale day names and the week's first day are read in. Keyed on the
+ * configuration, so a language change re-reads both; shared, so the repeat-day
+ * buttons, the alarm summaries and the week-start picker never disagree.
+ */
+@Composable
+internal fun rememberLocale(): Locale {
+    val configuration = LocalConfiguration.current
+    return remember(configuration) { Locale.getDefault() }
+}

app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/ClockSettingsScreen.kt

@@ -101,7 +101,7 @@ internal fun ClockSettingsScreen(
         Spacer(Modifier.height(24.dp))
         GroupedRow(
             title = stringResource(R.string.settings_week_start),
-            summary = weekStartText(state.weekStart),
+            summary = weekStartSummary(state.weekStart),
             position = Position.Alone,
             onClick = { showWeekStart = true },
         )

app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/SettingsScreen.kt

@@ -63,6 +63,7 @@ import de.jeanlucmakiola.floret.crash.CrashReporter
 import de.jeanlucmakiola.floret.crash.openIssueTracker
 import de.jeanlucmakiola.floret.crash.submitCrashReport
 import de.jeanlucmakiola.floret.identity.predictiveBackExit
+import de.jeanlucmakiola.floret.identity.rememberReduceMotion
 
 /** The settings sub-screens reached from the hub's category rows. */
 private enum class SettingsSection { Appearance, Alarms, Timers, Clock }
@@ -182,9 +183,11 @@ fun SettingsScreen(
 @Composable
 private fun SlideInSection(visible: Boolean, content: @Composable () -> Unit) {
     val slideSpec = MaterialTheme.motionScheme.defaultSpatialSpec<IntOffset>()
+    // Reduced motion fades it in, as predictiveBackExit already fades it out.
+    val enter = if (rememberReduceMotion()) fadeIn() else slideInHorizontally(slideSpec) { it } + fadeIn()
     AnimatedVisibility(
         visible = visible,
-        enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+        enter = enter,
         exit = predictiveBackExit(),
     ) { content() }
 }

app/src/main/java/de/jeanlucmakiola/clockula/ui/settings/WeekStartPicker.kt

@@ -1,23 +1,31 @@
 package de.jeanlucmakiola.clockula.ui.settings
 
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.remember
-import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.clockula.R
 import de.jeanlucmakiola.clockula.domain.WeekStartPref
 import de.jeanlucmakiola.clockula.domain.resolveFirstDay
+import de.jeanlucmakiola.clockula.ui.common.rememberLocale
 import de.jeanlucmakiola.floret.components.GroupedHint
 import de.jeanlucmakiola.floret.components.OptionPicker
 import java.time.format.TextStyle
-import java.util.Locale
 
 /** A pinned day is the locale's own weekday name, so no per-day string is needed. */
 @Composable
 internal fun weekStartText(pref: WeekStartPref): String = when (pref) {
     WeekStartPref.Auto -> stringResource(R.string.settings_week_start_auto)
-    is WeekStartPref.Day -> pref.day.getDisplayName(TextStyle.FULL, rememberDefaultLocale())
+    is WeekStartPref.Day -> pref.day.getDisplayName(TextStyle.FULL, rememberLocale())
+}
+
+/** The row's summary: a pinned day, or "Automatic (Monday)" with the day it resolves to. */
+@Composable
+internal fun weekStartSummary(pref: WeekStartPref): String = when (pref) {
+    WeekStartPref.Auto -> stringResource(
+        R.string.settings_week_start_auto_row,
+        weekStartText(WeekStartPref.Day(pref.resolveFirstDay(rememberLocale()))),
+    )
+    is WeekStartPref.Day -> weekStartText(pref)
 }
 
 /**
@@ -32,7 +40,7 @@ internal fun WeekStartPicker(
     onSelect: (WeekStartPref) -> Unit,
     onDismiss: () -> Unit,
 ) {
-    val locale = rememberDefaultLocale()
+    val locale = rememberLocale()
     OptionPicker(
         title = stringResource(R.string.settings_week_start),
         header = { GroupedHint(stringResource(R.string.settings_week_start_hint), verticalPadding = 8.dp) },
@@ -53,9 +61,3 @@ internal fun WeekStartPicker(
         onDismiss = onDismiss,
     )
 }
-
-@Composable
-private fun rememberDefaultLocale(): Locale {
-    val configuration = LocalConfiguration.current
-    return remember(configuration) { Locale.getDefault() }
-}

app/src/main/res/values/strings.xml

@@ -370,6 +370,7 @@
     <string name="settings_week_start">Week starts on</string>
     <string name="settings_week_start_auto">Automatic</string>
     <string name="settings_week_start_auto_summary">Currently %1$s</string>
+    <string name="settings_week_start_auto_row">Automatic (%1$s)</string>
     <string name="settings_week_start_hint">The day every week begins on, in alarms and bedtime.</string>
     <string name="screen_saver_title">Screen saver</string>
     <string name="screen_saver_style">Clock style</string>

app/src/test/java/de/jeanlucmakiola/clockula/data/backup/BackupCodecTest.kt

@@ -212,6 +212,13 @@ class BackupCodecTest {
         assertThat((decoded as BackupResult.Success).content.settings.weekStart).isEqualTo(WeekStartPref.Auto)
     }
 
+    @Test
+    fun `a null week start follows the locale rather than rejecting the file`() {
+        val decoded = BackupCodec.decode(settingsOnly(""""week_start": null"""))
+
+        assertThat((decoded as BackupResult.Success).content.settings.weekStart).isEqualTo(WeekStartPref.Auto)
+    }
+
     private fun settingsOnly(settings: String): String =
         """{ "format": "clockula-backup", "version": 1, "exportedAt": 0, "settings": { $settings } }"""
 

docs/BACKUP.md

@@ -221,7 +221,7 @@ alarm or timer inherits depends on it. The same goes for
 
 `week_start` is the first day of the week (#30): `AUTO`, which follows the
 locale, or a day name from `MONDAY` to `SUNDAY`. A file without it, or with a
-value this version does not know, restores `AUTO`.
+value this version does not know or `null`, restores `AUTO`.
 
 Every numeric/duration value is clamped on *apply* using the same ranges and encoding
 as the existing preference setters, never on parse.